Adhesion promoter and self-priming arylcyclobutene resin compositions

ABSTRACT

A method of hydrolyzing an alkoxysilane which comprises adding sufficient water to hydrolyze at least one alkoxy group, optionally, in the presence of acidic or basic catalysts.

BACKGROUND OF THE INVENTION

The present invention relates to a coating composition and moreparticularly to a solution of a hydrolyzed or partially hydrolyzedalkoxysilane, and an arylcyclobutene resin, and to a solventless processfor preparing hydrolyzed or partially hydrolyzed alkoxysilanes.

It is known to use hydrolyzed alkoxysilanes as adhesion promoters orcoupling agents for various polymeric materials. The hydrolyzedalkoxysilanes are typically used as a primer layer, i.e., they areapplied to the substrate first, followed by application of the polymericmaterial. The alkoxysilanes are typically hydrolyzed to form aqueousand/or protic solutions before being applied as thin films. However,most organoalkoxy-silanes are not soluble in water and must be dissolvedfirst in a compatible organic solvent, such as an alcohol.Unfortunately, upon application of the aqueous alkoxysilane/alcoholmixture, a discontinuous film forms which contains voids where the filmhas not covered the substrate.

It is also known that a hydrolyzed alkoxysilane can be used as anadhesion promoter primer layer for arylcyclobutene resins. For example,in Proc. MRS, Vol. 323, pg. 365, 1994, Adhesion of Cyclotene™ (BCB)Coatings on Silicon Substrates, a prehydrolyzed solution of3-methacryl-oxypropyltrimethoxysilane (MOPS) in methanol was used as anadhesion promoter for Cyclotene™. However, the MOPS solution isextremely difficult to deposit uniformly, forming agglomerates on thesurface, which leads to reliability problems when used in fabricatedparts.

It is also known to hydrolyze specific silanes in the absence of asolvent. U.S. Pat. No. 3,350,345 to Vanderbilt et al. describes aprocess of hydrolyzing specific silanes by adding water to hydrolyze atleast one but not all of the alkoxy groups. The specific silanes havereactive groups such as amino, mercapto, carboxyl or cyano, whichself-catalyze the hydrolysis process.

Accordingly, it remains highly desirable to provide coating compositionscontaining an arylcylcobutene which does not exhibit the foregoingdisadvantages as well as to provide a process which does not use anorganic solvent for hydrolyzing alkoxysilanes.

SUMMARY OF THE INVENTION

One aspect of the present invention is a coating composition comprising:

a) a hydrolyzed or partially hydrolyzed alkoxysilane,

b) a solvent, and

c) an arylcyclobutene.

In a preferred embodiment, the coating composition comprises:

a) a hydrolyzed or partially hydrolyzed alkoxysilane of the formula:##STR1## wherein R is C₁ -C₆ alkylidene, C₁ -C₆ alkylene, arylene, or adirect bond; Y is C₁ -C₆ alkyl, C₂ -C₆ alkenyl, aryl, 3-methacryloxy,3-acryloxy, 3-aminoethyl-amino, or 3-amino; R' is independently in eachoccurrence C₁ -C₆ alkyl; and Z is C₁ -C₆ alkyl, C₂ -C₆ alkenyl or OR';

(b) a solvent, and

(c) an arylcyclobutene.

In a most preferred embodiment, the coating composition comprises apartially hydrolyzed 3-methacryloxypropyltrimethoxysilane, mesitylene,and a bisbenzocyclobutene.

In another aspect, the present invention is a method of hydrolyzing analkoxysilane which comprises adding sufficient water to hydrolyze atleast one alkoxy group, optionally, in the presence of acidic or basiccatalysts.

In a preferred embodiment, 3-methacryloxypropyltrimethoxysilane ispartially hydrolyzed in the presence of hydrochloric acid.

The coating compositions of the present invention are useful in avariety of applications, including coatings for multichip modules, flatpanel displays and integrated circuits.

DETAILED DESCRIPTION OF THE INVENTION

The alkoxysilanes which can be employed in the coating composition ofthe present invention can be any alkoxysilane or mixture thereof whichare capable of forming a solution with the arylcyclobutene components inan organic liquid. Preferably, the alkoxysilanes are dialkoxy ortrialkoxysilanes. More preferably, the alkoxysilanes correspond to theformula: ##STR2## wherein R is C₁ -C₆ alkylidene, C₁ -C₆ alkylene,arylene, or a direct bond; Y is C₁ -C₆ alkyl, C₂ -C₆ alkenyl, aryl,3-methacryloxy, 3-acryloxy, 3-aminoethylamino, or 3-amino; R' isindependently in each occurrence C₁ -C₆ alkyl; and Z is C₁ -C₆ alkyl, C₂-C₆ alkenyl or OR'.

The term alkylidene refers to aliphatic hydrocarbon radicals whereinattachment occurs on the same carbon. The term alkylene refers toradicals which correspond to the formula --(C_(n) H_(2n))--. The termaryl refers to an aromatic radical, aromatic being defined as containing(4n+2)_(II) electrons as described in Morrison and Boyd, OrganicChemistry, 3rd ed., 1973. The term arylene refers to an aryl radicalhaving two points of attachment. The term alkyl refers to saturatedaliphatic groups such as methyl, ethyl, etc. Alkenyl refers to alkylgroups containing at least one double bond, such as ethylene, butylene,etc. The groups previously described may also contain othersubstituents, such as halogens, alkyl groups, aryl groups, and heterogroups such as ethers, esters, amides; or acidic or basic moieties, i.e.carboxylic, epoxy, amino, sulfonic, or mercapto, provided thealkoxysilane remains compatible with the other components of the coatingcomposition.

Preferably the alkoxysilane is a trialkoxysilane such as3-methacryloxypropyltrialkoxysilane, 3-aminopropyltrialkoxysilane, avinyltrialkoxysilane, a benzyltrialkoxysilane, abicycloheptenyltrialkoxysilane, a cyclohexenylethyltrialkoxysilane, acyclohexyltrialkoxysilane, a cyclopentadienylpropyltrialkoxysilane, a7-octa-1-enyltrialkoxysilane, a phenethyltrialkoxysilane or anallyltrialkoxysilane. The alkoxysilane is most preferably3-methacryloxypropyltrimethoxysilane.

The alkoxysilanes are preferably hydrolyzed or partially hydrolyzed bythe solventless process described hereinafter and can be used directlyin the coating compositions. Alternatively, the hydrolyzed or partiallyhydrolyzed alkoxysilane can be prepared in a volatile solvent. In suchcase, the solvent must be removed prior to being incorporated into thecoating composition of the present invention.

The alkoxysilanes useful in the practice of the present invention can bemade by techniques well known in the art such as exemplified inEncyclopedia of Chemical Technology, Third Edition, Volume 20, pgs.,916-918, 1982 and Silane Coupling Agents by Edwin P. Plueddemann,Chapter 2, pgs. 30-31, 1982.

The solvent used in the film forming coating composition of the presentinvention can be any organic liquid or mixture of two or more organicliquids in which the adhesion promoter and the arylcyclobutene aresoluble to produce a film forming composition. The solvent is preferablyan aprotic solvent or one which is highly immiscible with water.Representative examples of solvents include aromatic hydrocarbons,ketones, esters, ethers or mixtures thereof. Preferably, the solvent isan aromatic hydrocarbon, more preferably toluene, xylene, mesitylene oran alkylnaphthalene and most preferably mesitylene.

The arylcyclobutene used in the film forming coating compositions can beany arylcyclobutene which is capable of forming a solution with thehydrolyzed alkoxysilane in the organic liquid described previously.Arylcyclobutenes contain an aryl moiety to which one or more cyclobutenerings are fused. Examples of suitable aryl moieties include benzene,naphthalene, phenanthrene, anthracene, pyridine, a biaryl moiety, or 2or more aromatic moieties bridged by alkylene or cycloalkylene moieties.Preferred aryl moieties are benzene, naphthalene, biphenyl, binaphthyl,diphenyl alkane or diphenyl cycloalkane moieties. The more preferredaryl moiety is a benzene moiety.

Arylcyclobutenes and methods of making are well known in the art and areexemplified in U.S. Pat. No. 4,540,763 by Kirchoff, which isincorporated herein by reference.

Preferred arylcyclobutenes correspond to the formula: ##STR3## wherein Bis a direct bond or bridging member which comprises (1) a polyvalentinorganic radical, or (2) a polyvalent organic moiety which can contain(a) one or more heteroatoms comprising oxygen, sulfur, nitrogen, orphosphorus, or (b) one or more aromatic moieties; Ar is an aromaticradical which may be substituted; R is separately in each occurrencehydrogen or an electron-withdrawing or electron-donating substituent; mis an integer of 1 or 2 and n is an integer from 1 to 5, with theproviso that B can only be a direct bond wherein n is 2.

In a more preferred embodiment, the arylcyclobutene is benzocyclobutene(the aromatic moiety is benzene and m is 1). Preferred benzocyclobutenescorrespond to the formula: ##STR4## wherein a is separately in eachoccurrence the integer 0, 1, 2 or 3; and B, R, and n are as definedhereinbefore. These materials are further defined and taught in U.S.Pat. No. 4,642,329 which is incorporated herein by reference.

Additional compounds corresponding to Formula II wherein B contains Siare further defined and taught in U.S. Pat. No. 4,999,449 which isincorporated herein by reference.

Other U.S. Patents which disclose exemplary benzocyclobutene resinsinclude Pat. Nos. 4,540,763; 4,687,823; 4,730,030; 4,759,874; 4,783,514;4,812,588; 4,826,997; 4,973,636; and 5,025,080, as well as WO 9312055.

Mixtures of two or more different arylcyclobutenes can also be employed.In addition, the composition can contain other monomers copolymerizablewith the arylcyclobutene such as ethylenically unsaturated monomers,e.g.,styrenes, acrylates, divinylbenzene, and methacrylates, acetylenicmonomers, e.g., phenyl acetylene and diphenyl acetylene, and othermonomers capable of addition polymerization with the arylcyclobutene.

The arylcyclobutene can be used in the form of a monomer, an oligomer, apolymerized or copolymerized resin, a prepolymer, i.e., a partiallypolymerized or copolymerized arylcyclobutene having reactivepolymerization sites which provide for further polymerization, or acombination thereof.

The coating compositions may also contain other additives to impartother useful properties to the film forming compositions. Such additivesinclude but are not limited to photocrosslinking agents, energy transferagents (exemplified in WO 9312055), anti-oxidants (exemplified in U.S.Pat. No. 5,185,391) and the like.

The amounts of the alkoxysilane solvent and arylcyclobutene employed inthe coating composition is dependent upon a number of factors includingthe specific end-use application and the properties desired. One suchapplication is an adhesion promoter primer coating. As mentioned, apromoter primer coating provides adhesive bonding between the surface towhich it is applied and a subsequently applied coating layer.Alternatively, the composition is a self-priming coating. In such acase, the hydrolyzed alkoxysilane functions to provide adhesive bondingbetween the surface to which self priming formulation is applied and theresultant arylcyclobutene film. In addition, it can also provideadhesive bonding to a subsequently applied surface. In general, a primercomposition normally will contain lesser amounts of the arylcyclobutenethan when the composition is used as a self-priming composition.

In general, regardless of its intended end-use, the compositioncomprises from about 0.01 to about 10 weight percent hydrolyzedalkoxysilane, from about 10 to about 99.9 weight percent solvent, andfrom about 0.01 to about 90 weight percent arylcyclobutene, said weightpercents being based on the total weight of the composition.

In general, when applied as an adhesion promoter primer coatingapplication, the composition comprises from about 0.01, more preferablyfrom about 0.2, most preferably from about 1.5 weight percent, to about10, more preferably about 5, and most preferably to about 2.5 weightpercent of hydrolyzed alkoxysilane; from about 75, more preferably about90, and most preferably about 92.5 weight percent to about 99.9, morepreferably about 99.5, and most preferably about 98 weight percent ofsolvent, and from about 0.01, more preferably from about 1, and mostpreferably from about 2 weight percent to about 20, more preferablyabout 10, and most preferably about 5 weight percent of arylcyclobutene,said weight percents being based on the total weight of the composition.

Alternatively, when employed as a self-priming coating application thecomposition comprises from about 0.01, more preferably from about 0.2,and most preferably from about 0.5 weight percent to about 5, morepreferably to about 3, and most preferably to about 1 weight percent ofhydrolyzed alkoxysilane; from about 10, more preferably from about 40,and most preferably from about 55 weight percent to about 95, morepreferably to about 90 and most preferably to about 80 weight percent ofsolvent; and from about 5, more preferably from about 10, and mostpreferably from about 20 weight percent to about 90, more preferably toabout 80, and most preferably to about 65 weight percent ofarylcyclobutene, said weight percents being based on the total weight ofthe composition.

In coating articles for use in electronics applications such asmultichip modules, flat panel displays, integrated circuits, and thelike, representative substrates which can be coated with the coatingcomposition include metals such as aluminum, copper, titanium andchrome; ceramics such as alumina, silica, MgO, BeO, including spinels,aluminum nitride, boron nitride, silicon nitride, gallium arsenide; andglasses such as fiber glass, lime glass, flint glass, borosilicateglass, Pyrex and Vycor. Preferably, if the substrate is a metal such ascopper, it is treated with an etchant such as 1 percent acetic acidprior to application of the coating composition. Substrates commonlyused in high density electronic circuitry, such as silicon, thermallyoxidized silicon, GaAs, alumina and aluminum are commonly treated byprocesses such as oxygen plasma etching or RCA clean, to control surfacechemistry.

While the coating compositions can be applied using any of thetechniques well known in the art, such as spray, brush, dip, miniscous,extrusion, capillary, curtain, roll coating and the like, they aretypically advantageously applied at room temperature using conventionalspin-coating techniques.

In this application, the coating composition can be used as an adhesionpromoter primer layer or as a self-priming BCB polymer layer. Typicalthicknesses for adhesion promoter primer layers are between about 100 toabout 1000 Angstroms, whereas the thickness of the self-priming polymerlayer can vary from about 0.5 to about 25 microns. Multiple layers maybe prepared using the composition either as an adhesion promoter primeror a self-priming polymer layer. The multi-layer coatings typicallyrange between about 10 to about 500 microns and are preferably fromabout 50 to about 200 microns. The coating compositions of the presentinvention may also be subsequently coated with other polymeric materialssuch as other arylcyclobutene polymers and copolymers or any otherpolymeric material which will bond with the coating composition.

After being applied, the coating compositions can be crosslinked,photocrosslinked, cured or soft cured. Photodefineable arylcyclobutenesare typically photocrosslinked prior to further cure. Conventionalcuring techniques such as electron beam, ultra violet, thermalradiation, or convection can also be employed.

The degree of polymerization will depend upon the application involved.For instance, when additional layers will be applied, a soft cure orcrosslinking of about 80 to 85 percent (as measured by FTIR) ispreferred and can be accomplished, for example, by heating at about 220°C. for about 30 minutes. In the final stage of curing, crosslinking ofmore than about 95 percent can be achieved, for example, by heating at250° C. for about 1 hour.

The alkoxysilane used in the coating composition of the presentinvention is preferably prepared using a solventless process in whichthe alkoxysilane is contacted with a sufficient amount of water tohydrolyze at least one alkoxy group. Optionally, an acidic or basiccatalyst is also employed.

The alkoxysilanes used in the process of hydrolysis can be anyalkoxysilane which has no groups sufficiently acidic or basic tocatalyze the hydrolysis reaction. Preferably, the alkoxysilanes arethose which have been described previously in Formula (I), with theproviso that R is not 3-aminoethylamino or 3-amino and R, Y, and Z mayonly be further substituted with moieties which are substantially inertor nonreactive in the hydrolysis reaction. Examples of such inertsubstituents include but are not limited to halogens, alkyl, and arylgroups. More preferably, the alkoxysilane is a trialkoxysilane and ismost preferably 3-methacryloxypropyltrimethoxysilane.

The amount of water most advantageously employed in the hydrolysisreaction is dependent upon a variety of factors including the degree ofhydrolysis desired. To achieve complete hydrolysis, a stoichiometricamount of water to completely hydrolyze the alkoxysilane is 1 molarequivalent of water for each molar equivalent of alkoxy group present onthe alkoxysilane. In practice, less than a stoichiometric amount ofwater is required for complete hydrolysis since water is formed bycondensation reactions during the hydrolysis. The amount of water usedfor desired hydrolysis in the present invention is preferably no morethan a stoichiometric amount. Preferably from about 10 percent to about80 percent of the stoichiometric amount of water needed for totalhydrolysis is used, more preferably from about 30 percent to about 60percent and most preferably about 40 percent.

The water used in the hydrolysis should be purified. Preferably, thewater is deionized and microfiltered.

The optional, but generally preferred, acidic or basic catalysts may beany acidic or basic compound which will catalyze the hydrolysis of thealkoxysilane. Examples of acidic catalysts include but are not limitedto hydrochloric acid, sulfuric acid, trifluoroacetic acid, chloroaceticacid, methane sulfonic acid, and phosphoric acid. Examples of basiccatalysts include but are not limited to potassium hydroxide, sodiumhydroxide, and 3-aminopropyltrialkoxysilanes. More advantageously, thecatalyst is acidic. Preferably, the acidic catalyst is hydrochloricacid, sulfuric acid, trifluoroacetic acid, methane sulfonic acid, orphosphoric acid. More preferably, the catalyst is hydrochloric acid,sulfuric acid, trifluoroacetic acid, or phosphoric acid, and mostpreferably hydrochloric acid.

The catalyst is used in amounts sufficient to catalyze the hydrolysisreaction. The amount of catalyst most advantageously employed willdepend upon a number of factors including the desired rate ofhydrolysis, the catalyst, the alkoxysilane used, and the degree ofhydrolysis desired. Preferably, the catalyst is present in amounts fromabout 0 ppm to about 50 ppm based on the amount of hydrolyzedalkoxysilane. More preferably, the catalyst is present in amounts fromabout 2 ppm to about 40 ppm and most preferably between about 4 ppm toabout 30 ppm, based on the amount of hydrolyzed alkoxysilane.

Hydrolysis of alkoxysilanes produces a mixture of nonhydrolyzed,partially hydrolyzed, fully hydrolyzed and oligomerized alkoxysilanes.Oligomerization occurs when a hydrolyzed or partially hydrolyzedalkoxysilane reacts with another alkoxysilane to produce water and anSi--O--Si bond. As used herein, the term "hydrolyzed alkoxysilane"encompasses any level of hydrolysis, partial or full, as well asoligomerized.

In hydrolyzing the alkoxysilane, the alkoxysilane, water, and optionalcatalyst are mixed until the desired hydrolysis is complete. While thetime to complete hydrolysis will vary depending on a number of factors,including the specific reactants employed, in general, hydrolysis iscomplete in a time from about 2 minutes to about 5 hours, preferably forabout 4 minutes to about 2 hours, and more preferably for about 10minutes to about 1 hour.

In general, the alkoxysilane, water, and catalyst initially form atwo-phase mixture which upon agitation and continuation of thehydrolysis reaction, becomes a single phase. The time required to form asingle phase is dependent upon the alkoxysilane used and the temperatureat which the ingredients are mixed; with less time being required athigher temperatures. Depending upon the catalyst type, its concentrationand the alkoxysilane used, hydrolysis may be complete by the time asingle phase is obtained, or additional time may be required to completehydrolysis. In general, the mixture is agitated for about 10 minutes toabout 2 hours after a single phase is obtained to complete thehydrolysis reaction. The temperature at which hydrolysis is conducted ispreferably from about 15° C. to about 100° C., more preferably fromabout 20° C. to about 50° C. and most preferably from about 20° C. toabout 25° C.

Alternatively, the hydrolysis may be conducted in the absence of acatalyst. In this procedure, the alkoxysilane is mixed with water andstirred for a sufficient period of time for the desired extent ofhydrolysis to occur. This method may take up to several days dependentupon the alkoxysilane and the temperature at which hydrolysis occurs. Insome applications this method may be preferred when residual catalystlevels have an adverse effect on subsequent use of the alkoxysilane.

The following examples are set forth to illustrate the present inventionand should not be construed to limit its scope. In the examples, allparts and percentages are by weight unless otherwise indicated.

EXAMPLE 1

12.5 g (0.0503 mol) of 3-Methacryloxypropyltrimethoxysilane (MOPS)containing 29 ppm HCl, and 1.09 g (0.0604 mol) deionized andmicrofiltered water (pH 6.8) (40 percent of theoretical needed forcomplete hydrolysis) is combined in a 2 oz. bottle. The two-phasemixture is agitated at 23° C. Hydrolysis proceeds and a single phase isproduced in 8 minutes. Proton NMR (DCC13; by measuring methanolby-product formation) indicates that hydrolysis is complete in anadditional 8 to 15 minutes. At 15, 30, and 60 minute reaction times, 1.0g samples are removed and diluted with 39.0 g methanol to give solutionsat 2.5 weight percent solids.

Approximately 10 mLs of the solution are dispensed with a syringethrough a 0.5 mm filter onto oxidized silicon wafers rotating at 3000RPM. The morphology of the resulting residue is observed with opticalmicroscopy. CYCLOTENE™ 3022 resin, (a formulation manufactured by TheDow Chemical Company of tetramethyldivinylsiloxane bisbenzocyclobuteneresin in mesitylene containing 4.0 weight percent (based on solids)AgeRite™ MA antioxidant (manufactured by B. F. Goodrich)) issubsequently applied at a thickness of 10 microns, and cured at 250° C.for one hour. Delamination of the cured coatings is evaluated bymicroindentation (as described in The Determination of Bond Strength ofPolymeric Films by Indentation Debonding by H. D. Conway and J. P. R.Thomsin, in J. Adhesion Sci. Technol. 3, 227, 1988). Values of bondstrength are obtained from the level of delamination observed by opticalmicroscopy.

The effects of water level and reaction time on adhesion performance ofmethanol-based hydrolyzed MOPS adhesion promoters were observed. Afterapplication of the adhesion promoter, the morphology of the depositedresidue was discontinuous, appearing in the form of droplets.

In a similar fashion, adhesion promoter samples are prepared based onwater levels which corresponded to 20, 60, 80, and 100 percenthydrolysis. Results are given in Table I.

                  TABLE 1                                                         ______________________________________                                                  Reaction                                                              Water Time  Adhesion                                                          (%) (min) Morphology (MPa)                                                  ______________________________________                                        20        15          droplets   187 ± 3.9                                   20 30 droplets 172 ± 11.6                                                  20 60 droplets 171 ± 3.1                                                   40 15 droplets 187 ± 7.7                                                   40 30 droplets 192 ± 2.4                                                   40 60 droplets 191 ± 7.7                                                   60 15 droplets --                                                             60 30 droplets 178 ± 8.2                                                   60 60 droplets 152 ± 8.7                                                   80 15 droplets 172 ± 3.8                                                   80 30 droplets 162 ± 12.9                                                  80 60 droplets 141 ± 9.7                                                   100  15 droplets 126 ± 3.9                                                 100  30 droplets 118 ± 3.7                                                 100  60 droplets 124 ± 3.7                                                 No promoter  No 73 ± 4.8                                                     promoter                                                                  ______________________________________                                    

EXAMPLE 2

A partially hydrolyzed MOPS is prepared using the same techniques usedin Example 1 (40 percent water). After 1 hour reaction time at ambienttemperature, portions of the neat hydrolyzed alkoxysilane are added to 5percent solutions of Cyclotene™ 3022 in mesitylene to yield a series ofadhesion promoter solutions in amounts to give solutions containing 0.5,1.0, 2.5, and 5.0 percent of the hydrolyzed alkoxysilane. Each solutionis evaluated for processability and adhesion performance(microindentation). Results are given in Table II.

                  TABLE II                                                        ______________________________________                                        Hydrolyzed MOPS                                                                 Concentration Film-Forming Adhesion                                           (wt %) Ability (MPa)                                                        ______________________________________                                        0.5             film-forming                                                                             206 ± 4.0                                         1.0 film-forming 183 ± 8.1                                                 2.5 film-forming 184 ± 6.6                                                 5.0 film-forming 198 ± 3.0                                                 2.5% in isopropanol droplets 195 ± 6.2                                     2.5% in methanol droplets 204 ± 6.5                                      ______________________________________                                    

Hydrolyzed MOPS adhesion promoter formulations containing CYCLOTENE™3022 in mesitylene provide film forming compositions with good adhesionperformance.

EXAMPLE 3

A partially hydrolyzed MOPS is prepared using the same conditions usedin Example 1 (40 percent water). After 1 hour reaction time at 23° C.,portions of the neat partially hydrolyzed MOPS are added to 63 percentsolutions of Cyclotene™ 3022 in mesitylene to yield a self-primingformulation with 0.5 weight percent of the hydrolyzed MOPS. Thissolution is compared to the unprimed solution for stability,processability, and adhesion performance (microindentation) (ComparativeExample A). Results are given in Table III.

                  TABLE III                                                       ______________________________________                                        Hydrolyzed MOPS                                                                 Concentration Film Thickness Adhesion                                         (wt %) (μm) (MPa)                                                        ______________________________________                                        0.5             12.87       253 ± 10.0                                       0.5 13.37 251 ± 3                                                          0.5 13.24 255 ± 1.6                                                        0.5 13.09 251 ± 3.5                                                        Comparative                                                                   Example A                                                                     0 13.09 106 ± 5.1                                                          0 13.08 97 ± 3.9                                                         ______________________________________                                    

A self-priming CYCLOTENE™ 3022 formulation containing hydrolyzed MOPSadhesion promoter has considerably improved adhesion performance.

EXAMPLE 4

A partially hydrolyzed MOPS is prepared using the same conditions usedin Example 1 (40 percent water). After 1 hour reaction time at ambienttemperature, 0.084 g portions of the neat hydrolyzed MOPS are added tothe following photosensitive BCB formulation:

14.93 g1,3-bis(2-bicyclo(4.2.0)octa-1,3,5-trien-3-ylethenyl)-1,1,3,3-tetramethyldisiloxane resin

0.31 g 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone

0.116 g 4,4'-diazidophenyl sulfone

0.116 g 1,2-dihydro-2,2,4-trimethylquinoline

17.3 g mesitylene

The adhesion promoter and photosensitive BCB solution were shaken andallowed to stand until bubbles from the agitation were gone. Thisproduces a self-priming photosensitive formulation with 0.5 percent ofthe hydrolyzed MOPS coupling agent. This solution is compared to theunprimed solution for stability, processability, and adhesionperformance (microindention) (Comparative Example B). Results are givenin Table IV.

                  TABLE IV                                                        ______________________________________                                        Hydrolyzed MOPS                                                                 Concentration Film Thickness Adhesion                                         (wt %) (μm) (MPa)                                                        ______________________________________                                        0.5             11.91      291 ± 9.0                                         0.5 11.96 289 ± 4.7                                                        Comparative                                                                   Example B                                                                     0 11.71  98 ± 3.3                                                          0 11.84 101 ± 1.6                                                        ______________________________________                                    

Self-priming photodefinable benzocyclobutene formulations containinghydrolyzed MOPS adhesion promoter provide substantial adhesionenhancement.

EXAMPLE 5

12.5 g (0.0503 mol) of 3-Methacryloxypropyltrimethoxysilane (MOPS), 1.09g (0.0604 mol) of 0.01 N aqueous HCl and 40 percent of the theoreticalamount of deionized and microfiltered water (pH 6.8) needed for totalhydrolysis are combined in a 2 oz. bottle. This acid level represents 30ppm HCl in the hydrolyzed MOPS. The two-phase mixture is stirred atambient temperature (23° C.). Hydrolysis proceeds such that a singlephase is produced in 8 minutes. In the absence of the 30 ppm HCl, themixture does not clear to one phase (little or no reaction) even after48 hours.

The experiment is repeated using 0.0050 N (15 ppm HCl) and 0.0025 N HCl(7.5 ppm HCl) and 0.0100, 0.0050, and 0.0025 N H₂ SO₄. Results are givenin Table V.

                  TABLE V                                                         ______________________________________                                                         Time to Form Single                                            Acid Concentration Phase (min)                                              (N)              HCl      H.sub.2 SO.sub.4                                    ______________________________________                                        0.0100            8        8                                                    0.0050 14 20                                                                  0.0025 44 75                                                                ______________________________________                                    

The experiment is repeated to define the hydrolysis temperature, HClcatalyst level, time required to form a single phase and time requiredfor complete hydrolysis (40 percent of theoretical). Proton NMR is usedto measure time for complete hydrolysis; single phase times are observedvisually. Results are given in Table VI.

                  TABLE VI                                                        ______________________________________                                                                Single  Complete                                        HCl Reaction Phase Hydrolysis                                                 conc. (ppm) Temp. (°C.) (min.) (min.)                                ______________________________________                                        0         23            4320    8640                                            0 40 1140 2460                                                                6 23 40 60                                                                    15 23 15 60                                                                   30 23 8 40                                                                    30 30 5 30                                                                    30 35 4 20                                                                  ______________________________________                                         The single phase and complete hydrolysis columns refer to the amount of       time required to reach these conditions.                                 

Although hydrolysis will occur in the absence of HCl, the reaction timeis significantly shortened by the presence of trace amounts of HCl. Thereaction temperature also greatly effects the time needed for thehydrolysis reaction, wherein higher temperatures decrease the amount oftime significantly.

EXAMPLE 6

12.5 g (0.0565 mol) of 3-Aminopropyltriethoxysilane (3-APS) and 1.22 g(0.0678 mol) deionized and microfiltered water (pH 6.8; 40 percent oftheoretical needed for total hydrolysis) are combined in a 2 oz. bottle.The two-phase mixture is stirred magnetically at ambient temperature(23° C.). Hydrolysis proceeds such that a single phase is produced inabout 60 minutes. Proton NMR (DMSO-d₆ ; by following ethanol formation)indicates that hydrolysis is essentially complete at 60 minutes. Thismaterial is used to make a self-priming formulation similar to that ofExample 3.

EXAMPLE 7

11.87 g (0.0478 mol) of 3-Methacryloxypropyltrimethoxysilane (MOPS),0.56 g (0.00251 mol) of 3-aminopropyltriethoxysilane (3-APS);(MOPS/3-APS=95/5 mol ratio) and 1.08 g (0.0604 mol) of deionized andmicrofiltered water (pH 6.8; 40 percent of theoretical needed for totalhydrolysis) are combined in a 2 oz. bottle. The two-phase mixture isstirred at ambient temperature (23° C.). Hydrolysis proceeds such that asingle phase is produced in 25 minutes. Proton NMR (DMSO-d₆ ; byfollowing ethanol formulation) indicates that hydrolysis is essentiallycomplete at 30 minutes.

EXAMPLE 8

10.0 g (0.0657 mol) Vinyltrimethoxysilane and 1.46 g (0.0811 mol)aqueous 0.01 N HCl, and 40 percent of the theoretical amount needed fortotal hydrolysis of deionized and microfiltered water (pH 6.8); arecombined in a 2 oz. bottle. The two-phase mixture is stirred at ambienttemperature (23° C.). Hydrolysis proceeds such that a single phase isproduced in 1 minute. Proton NMR (DCCl₃) indicates that hydrolysis isessentially complete in 20 minutes.

A film forming formulation is prepared as in Example 2 using 2.5 percentof the 40 percent hydrolyzed vinyltrimethoxysilane, 5.0 percentCyclotene™ 3022, and 92.5 percent of mesitylene. The solution isevaluated for processability and adhesion performance bymicroindentation as in Example 2.

The formulation is film forming and adhesion is 244 MPa.

EXAMPLE 9

10.0 g (0.0616 mol) of Allyltrimethoxysilane, 1.33 g (0.0739 mol)aqueous 0.01 N HCl and 40 percent of the theoretical amount needed fortotal hydrolysis of deionized and microfiltered water (pH 6.8); arecombined in a 2 oz. bottle. The two-phase mixture is stirred at ambienttemperature (23° C.). Hydrolysis proceeds such that a single phase isproduced in 3 minutes. Proton NMR (DCCl₃) indicates that hydrolysis isessentially complete in 60 minutes.

A film forming adhesion promoter formulation is prepared as in Example 8using 2.5 weight percent of the 40 percent hydrolyzedallyltrimethoxysilane, 5.0 weight percent Cyclotene™ 3022, and 92.5weight percent of mesitylene. The solution is evaluated forprocessability and adhesion performance by microindentation as inExample 2.

The formulation is film forming and the adhesion is 147 MPa.

EXAMPLE 10

The following formulation is made to hydrolyze the methyl esters on3-methacryloxypropyltrimethoxysilane (MOPS):

48.06 g MOPS

48.06 g Methanol

4.81 g Water

0.96 g Trifluoroacetic Acid

The formulation is allowed to stand at room temperature for 24 hoursthen filtered through Strong Base Resin Ion Exchange Beads to remove thetrifluoroacetic acid. 90.35 g of methanol is added during the filtrationto rinse the solution from the beads completely. This material is placedin a vacuum evaporation flask in a warm water bath and the methanol isremoved to leave the residual hydrolyzed MOPS. The hydrolyzed MOPS isadded at 0.5 weight percent relative to solids to a 63 percent solidsformulation of Cyclotene™ 3022 in mesitylene. The resultant self-primedsolution is deposited by spin-coating onto a thermally oxidized siliconwafer to a thickness of 12.4 μm. The adhesion is measured bymicroindentation and measures 160.5 MPa±4.2 MPa. This value is animprovement when compared with typical values of 70 MPa obtained withnon-primed resin.

What is claimed is:
 1. A solventless process for hydrolyzing analkoxysilane of the formula: ##STR5## wherein R is C₁ -C₆ alkylidene, C₁-C₆ alkylene, arylene, or a direct bond; Y is C₁ -C₆ alkyl, C₂ -C₆alkenyl, aryl, 3-methacryloxy, or 3-acryloxy,; R' is independently ineach occurrence C₁ -C₆ alkyl; and Z is C₁ -C₆ alkyl, C₂ -C₆ alkenyl orOR',comprising adding not more than a stoichiometric amount of water,sufficient to hydrolyze at least one of the alkoxy groups, in thepresence of an acidic or basic catalyst.
 2. The process of claim 1wherein the alkoxysilane is 3-methacryloxypropyltrialkoxysilane.
 3. Theprocess of claim 1 wherein the catalyst is an acidic catalyst.
 4. Theprocess of claim 3 wherein the catalyst is selected from the groupconsisting of hydrochloric acid, sulfuric acid, methanesulfonic acid andphosphoric acid.
 5. The process of claim 4 wherein the catalyst ishydrochloric acid.
 6. The process of claim 1 wherein the catalyst is abasic catalyst.